diff --git a/src/ua.js b/src/ua.js
index 834b609..7b602fa 100644
--- a/src/ua.js
+++ b/src/ua.js
@@ -26,7 +26,9 @@ export function parseUA(ua) {
     return { device_type: null, os: null, browser: null };
   }
 
-  // device_type
+  // device_type — fallback is 'desktop' to mirror server.js
+  // wantsMobileView() (unrecognised UA → desktop page). Analytics
+  // stay consistent with what the user actually saw.
   let device_type = 'desktop';
   if (TABLET_UA_RE.test(ua))      device_type = 'tablet';
   else if (MOBILE_UA_RE.test(ua)) device_type = 'mobile';